Hole location targets and measurement systems, and methods for measuring a location of a hole

ABSTRACT

A hole location target includes a self-centering insert having a centerline and an optical target attached to the self-centering insert at a fixed position relative to the centerline of the self-centering insert. The optical target surface includes a two-dimensional pattern thereon.

FIELD

The present application relates to the field of hole location targets,hole location measurement systems, and methods for measuring a locationof a hole.

BACKGROUND

Touch-based coordinate measurement machines typically use a stylus tosweep an inside surface of a hole of a workpiece to determine acenterline of the hole, which takes significant time. Also, articleshaving holes to be measured by this technique are typically specificallydesigned to permit for insertion of and sweeping by a stylus of atouch-based coordinate measurement machine, thus restricting freedom ofdesign.

Accordingly, those skilled in the art continue with research anddevelopment in the field of hole location targets, hole locationmeasurement systems, and methods for measuring a location of a hole.

SUMMARY

According to a first embodiment, a hole location target includes aself-centering insert having a centerline and an optical target attachedto the self-centering insert at a fixed position relative to thecenterline of the self-centering insert. The optical target includes atwo-dimensional pattern thereon.

According to the first embodiment, a hole location measurement systemincludes a hole location target, a camera system, and a computer system.The hole location target includes a self-centering insert having acenterline and an optical target attached to the self-centering insertat a fixed position relative to the centerline of the self-centeringinsert, in which the optical target includes a two-dimensional patternthereon. The camera system is configured to capture images of thetwo-dimensional pattern on the optical target. The computer system isconfigured to measure three-dimensional locations of features of thetwo-dimensional pattern on the optical target and to extract a locationof a cylinder axis of the cylinder surface geometry.

According to the first embodiment, a method for measuring a location ofa hole includes centering an insert within a hole having a centerline.The optical target includes a two-dimensional pattern thereon at a fixedposition relative to the centerline of the insert. The method furtherincludes capturing images of the two-dimensional pattern on the opticaltarget, measuring three-dimensional locations of features of thetwo-dimensional pattern on the optical target, and extracting a locationof the centerline of the insert based on the three-dimensional locationsof features of the two-dimensional pattern on the optical target and thefixed position of the optical target relative to the centerline of theinsert.

According to a second embodiment, a hole location target includes aself-centering insert having a centerline and an optical target attachedto the self-centering insert at a fixed position relative to thecenterline of the self-centering insert. The optical target includes alight-emitting display. The light-emitting display includes atwo-dimensional pattern thereon.

According to the second embodiment, a hole location measurement systemincludes a hole location target, a camera system, and a computer system.The hole location target includes a self-centering insert having acenterline and an optical target attached to the self-centering insertat a fixed position relative to the centerline of the self-centeringinsert. The optical target includes a light-emitting display having atwo-dimensional pattern thereon. The camera system is configured tocapture images of the two-dimensional pattern of the optical target. Thecomputer system is configured to control modification of thetwo-dimensional pattern of the optical target and to determinethree-dimensional coordinates of the centerline of the self-centeringinsert from the images of the two-dimensional pattern of the opticaltarget.

According to the second embodiment, a method for measuring a location ofa hole includes centering an insert within a hole having a centerline.An optical target is attached to the insert at a fixed position relativeto the centerline of the insert. The optical target includes alight-emitting display having a two-dimensional pattern thereon. Themethod further includes capturing images of the two-dimensional patternof the optical target, modifying the two-dimensional pattern of theoptical target; and capturing images of the modified two-dimensionalpattern of the optical target.

According to a third embodiment, a hole location target includes aself-centering insert having a centerline and a laser beam emitterattached to the self-centering insert. The axis of the emitted laserbeam is concentric to the centerline of the self-centering insert.

According to the third embodiment, a hole location measurement systemincludes a hole location target, an optical system, and a computersystem. The hole location target includes a self-centering insert havinga centerline and a laser beam emitter attached to the self-centeringinsert, wherein the axis of the emitted laser beam is concentric to thecenterline of the self-centering insert. The optical system senses thelocation of the emitted laser beam at multiple distances from the laserbeam emitter. The computer system is configured to determinethree-dimensional coordinates of the centerline of the self-centeringinsert from the sensed locations of the emitted laser beam.

According to the third embodiment, a method for measuring a location ofa hole includes centering an insert within a hole having a centerlineand emitting a laser beam from a laser beam emitter attached to theinsert. The axis of the emitted laser beam is concentric to thecenterline of the insert. The method further includes sensing thelocation of the emitted laser beam at multiple distances from the laserbeam emitter and determining three-dimensional coordinates of thecenterline of the self-centering insert from the sensed locations of theemitted laser beam.

Other embodiments of the disclosed hole location targets, hole locationmeasurement systems, and methods for measuring a location of a hole willbecome apparent from the following detailed description, theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first exemplary hole location targetaccording to the first embodiment of the present description in anassembled state.

FIG. 2 is a perspective view of a second exemplary hole location targetaccording to the first embodiment of the present description in anassembled state.

FIG. 3 is an exploded perspective view of the hole location target ofFIG. 1.

FIG. 4A is cross-sectional view of the hole location target of FIG. 1inserted into a hole of a workpiece in a radially contracted state.

FIG. 4B is cross-sectional view of the hole location target of FIG. 4Ain a radially expanded state.

FIG. 5 is a representation of an exemplary hole location measurementsystem according to the first embodiment of the present description.

FIG. 6 is a flow diagram of an exemplary method for measuring a locationof a hole of a workpiece according to the first embodiment of thepresent description.

FIG. 7 is a perspective view of a first exemplary hole location targetaccording to a second embodiment of the present description in anassembled state.

FIG. 8 is a perspective view of a second exemplary hole location targetaccording to the second embodiment of the present description in anassembled state.

FIG. 9 is an exploded perspective view of the hole location target ofFIG. 7.

FIG. 10A is cross-sectional view of the hole location target of FIG. 7inserted into a hole of a workpiece in a radially contracted state.

FIG. 10B is cross-sectional view of the hole location target of FIG. 10Ain a radially expanded state.

FIG. 11 is a representation of an exemplary hole location measurementsystem according to the second embodiment of the present description.

FIG. 12 is a flow diagram of an exemplary method for measuring alocation of a hole of a workpiece according to the second embodiment ofthe present description.

FIG. 13 is a perspective view of an exemplary hole location targetaccording to a third embodiment of the present description in anassembled state.

FIG. 14 is an exploded perspective view of the hole location target ofFIG. 13.

FIG. 15A is cross-sectional view of the hole location target of FIG. 13inserted into a hole of a workpiece in a radially contracted state.

FIG. 15B is cross-sectional view of the hole location target of FIG. 15Ain a radially expanded state.

FIGS. 16A and 16B are representations of an exemplary hole locationmeasurement system according to the third embodiment of the presentdescription.

FIG. 17 is a flow diagram of an exemplary method for measuring alocation of a hole of a workpiece according to the third embodiment ofthe present description.

FIG. 18 is a flow diagram of an aircraft manufacturing and servicemethodology.

FIG. 19 is a block diagram of an aircraft.

DETAILED DESCRIPTION

FIGS. 1, 2, 3, 4A, 4B, 5, and 6 relate to hole location targets, holelocation measurement systems, and methods for measuring a location of ahole according to a first embodiment of the present description. FIGS.7, 8, 9, 10A, 10B, 11, and 12 relate to hole location targets, holelocation measurement systems, and methods for measuring a location of ahole according to a second embodiment of the present description. FIGS.13, 14, 15A, 15B, 16A, 16B, and 17 relate to hole location targets, holelocation measurement systems, and methods for measuring a location of ahole according to a third embodiment of the present description.

The hole location targets according to the first, second, and thirdembodiments each include a self-centering insert for inserting into ahole of a workpiece. It will be understood that the self-centeringinserts of the first, second, and third embodiments can include anystructures capable of inserting into the hole and self-centering acenterline of the self-centering insert to a respective centerline ofthe hole, such as a radially expandable bushing as shown in theillustrated examples.

In the illustrated examples, the hole location targets of the first andsecond embodiments are described below to include a radially expandablebushing in the form of expandable bellows, and the hole location targetof the third embodiment is described below to include a radiallyexpandable bushing in the form of an expandable collet. However, it willbe understood that the hole location targets of the first and secondembodiments can include a radially expandable bushing in the form of anexpandable collet, and the hole location target of the third embodimentcan include a radially expandable bushing in the form of an expandablebellows.

The hole location targets according to the first and second embodimentseach include an optical target attached to the self-centering insert ata fixed position relative to the centerline of the self-centeringinsert. It will be understood that the optical targets of the first andsecond embodiments can have any shapes. In the illustrated examples, theoptical target of the first embodiment are described below to include acylindrical exterior surface, and the optical target of the secondembodiment is described below to include flat rectangular surface.However, it will be understood that the optical target of the firstembodiment can include a flat rectangular surface, and the opticaltarget of the second embodiment can include a cylindrical exteriorsurface.

FIG. 1 is a perspective view of a first exemplary hole location targetaccording to the first embodiment of the present description in anassembled state. FIG. 2 is a perspective view of a second exemplary holelocation target according to the first embodiment of the presentdescription in an assembled state. FIG. 3 is an exploded perspectiveview of the hole location target of FIG. 1. FIG. 4A is cross-sectionalview of the hole location target of FIG. 1 inserted into a hole of aworkpiece W in a radially contracted state. FIG. 4B is cross-sectionalview of the hole location target of FIG. 4A in a radially expandedstate.

Referring to FIGS. 1, 2, 3, 4A, and 4B, the hole location target 10includes a first end 101 configured to be inserted into a hole H of aworkpiece W and a second end 102 opposite to the first end 101.

The hole location target 10 includes a self-centering insert 110 and anoptical target 120 attached to the self-centering insert 110. Theself-centering insert 110 is positioned near the first end 101 and theoptical target 120 is positioned near the second end 102 such that theself-centering insert 110 can be inserted into the hole H of theworkpiece and the optical target 120 can remain outside of the hole H ofthe workpiece W.

The self-centering insert 110 has a centerline 111 and the opticaltarget 120 is at a fixed position relative to the centerline 111 of theself-centering insert 110.

The self-centering insert 110 is configured to be inserted into the holeH of the workpiece W and to be self-centered such that the centerline111 of the self-centering insert 110 is positioned coaxially with arespective centerline C of the hole H of the workpiece W. By centeringthe centerline 111 of the self-centering insert 110 to be coaxial withthe centerline C of the hole H of the workpiece W, a method thatmeasures a location of the centerline 111 of the self-centering insert110 can be employed to determine a location of the centerline C of thehole H of the workpiece W. Furthermore, by making the optical target 120to be at a fixed position relative to the centerline 111 of theself-centering insert 110, a method that measures a location of theoptical target 120 can be employed to determine the location of thecenterline 111 of the self-centering insert 110 and, thus, to determinethe location of the centerline C of the hole H of the workpiece W.

In an aspect, the optical target 120 has a cylindrical exterior surface121 that is concentric to the centerline 111 of the self-centeringinsert 110. By making the cylindrical exterior surface 121 to beconcentric to the centerline 111 of the self-centering insert 110, amethod that measures a location of the cylindrical exterior surface 121can be employed to determine the location of the centerline 111 of theself-centering insert 110 and, thus, to determine the location of thecenterline C of the hole H of the workpiece W.

In the illustrated example, the self-centering insert 110 of the firstembodiment includes a radially expandable bushing 112. It will beunderstood that the radially expandable bushing 112 can include anytubular structure capable of inserting into the hole H of the workpieceW and capable of radially expanding to self-center the centerline 111 ofthe self-centering insert 110 to the centerline C of the hole H of theworkpiece W. In the illustrated example, the radially expandable bushing112 takes the form of an expandable bellows 114. In an alternativeexample, the radially expandable bushing 112 can take the form of anexpandable collet such as is described below with respect to the thirdembodiment.

The expandable bellows 114 of the present description is a tubularstructure in which an axial contraction of the expandable bellows 114translates into a radial expansion of expandable bellows 114 and anaxial expansion of the expandable bellows 114 translates into a radialcontraction of expandable bellows 114. In the illustrated example, theexpandable bellows 114 includes a first bellows end 115 and a secondbellows end 116 and one or more radial ridges 118 between the firstbellows end 115 and the second bellows end 116. By axially contractingthe expandable bellows 114, the one or more radial ridges 118 expandradially. By axially expanding the expandable bellows 114, the one ormore radial ridges 118 contract radially.

As shown in FIG. 4A, by axially expanding the expandable bellows 114,the one or more radial ridges 118 contract radially, thereby permittingthe expandable bellows 114 to be inserted into a hole H of a workpieceW. As shown in FIG. 4B, after inserting the expandable bellows into thehole H of the workpiece W, the expandable bellows 114 can be axiallycontracted to radially expand one or more radial ridges 118. The one ormore radial ridges 118 then contact the walls defining the hole H of theworkpiece W, thus causing a self-centering of the centerline 111 of theexpandable bellows 114 to the respective centerline C of the hole H ofthe workpiece W.

In the illustrated example, the optical target 120 is attached to theself-centering insert 110 such that the cylindrical exterior surface 121is concentric to the centerline 111 of the self-centering insert 110. Byway of example, the optical target 120 can be fixedly positioned to theself-centering insert 110 such that a position of the optical target isfixed with respect to a position of centerline 111 of the self-centeringinsert 110. The positioning of the optical target 120 with respect tothe position of centerline 111 of the self-centering insert 110 can bepermanent. In an example, the self-centering insert 110 and the opticaltarget 120 can be combined as a monolithic body. For improved precision,the self-centering insert 110 and the optical target 120 can be unitaryformed together as a monolithic body by one or more processes, such ascasting, molding, and additive manufacturing. In an aspect, thecylindrical exterior surface 121 of the optical target 120 has a surfacecylindricity of 5 μm or less (or a tolerance of concentricity of thecylindrical surface to the centerline that is within 5 μm) for improvedprecision of determining the centerline C of the hole H of the workpieceW.

In the illustrated example, the self-centering insert 110 includes abore 117 for accommodating a compression device 130. The compressiondevice 130 is configured to axially contract the expandable bellows 114.In the illustrated example, the compression device 130 includes a bolt140 and a nut 160.

As shown, the bolt 140 has a first bolt end 141 and a second bolt end142. The bolt 140 includes a bolt shaft 143 positioned at the first boltend 141 of the bolt 140 and a bolt head 144 positioned at the secondbolt end 142 of the bolt 140. The bolt shaft 143 includes a first shaftend 145 and a second shaft end 146. Exterior threads 147 are positionedat the first shaft end 145 of the bolt shaft 143, and the bolt head 144is joined to the second shaft end 146. The bolt head 144 includes afirst bolt head end 148 and a second bolt head end 149. A first boltface 151 is positioned at the first bolt head end 148, a second boltface 152 is positioned at the second bolt head end 149, and an outerbolt head surface 150 is positioned between the first bolt head end 148and the second bolt head end 149. The outer bolt head surface 150 cantake the form of a plurality of faces extending around a circumferenceof the bolt head 144 to improve retention of the bolt 140 within thebore 117 of the self-centering insert 110.

As shown, the nut 160 has a first nut end 161 and a second nut end 162.A first nut face 163 is positioned at the first nut end 161, a secondnut face 164 is positioned at the second nut end 162, and an outer nutsurface 165 is positioned between the first nut end 161 and the secondnut end 162. In an aspect, the outer nut surface 165 can include a nutgripping surface 166 configured to improve a grip of the nut 160. Asshown, the nut gripping surface 166 can take the form of a knurledsurface for manually torqueing of the nut 160. Alternatively, the nutgripping surface 166 can take other forms, such as the of a plurality offaces for torqueing the nut 160 with a tool. The nut bore 167 passesthrough the nut 160 from the first nut face 163 to the second nut face164, and the nut bore 167 includes interior threads 168 configured toengage with the exterior threads 147 of the bolt 140.

As shown, the bolt shaft 143 passes through bore 117 at a bellows endsurface 119 at the first end 101 of the self-centering insert 110 totarget end surface 124 at the second end 102 of the optical target 120,and the exterior threads 147 of the bolt 140 engage with the interiorthreads 168 of the nut 160. The first nut face 163 engages with theoptical target 120, and the first bolt face 151 engages with the firstbellows end 115 of the expandable bellows 114. Thus, the bolt 140 andnut 160 form a compression device 130 configured to contract theexpandable bellows 114 by turning the nut 160. However, the compressiondevice 130 is not limited to the above-described example. In anotherexample, the position of the bolt 140 and nut 160 can be reversed. Inyet another example, the compression device 130 may take the form of arachet or any other compression device configured to axially contractthe expandable bellows 114.

In the illustrated example, the hole location target 10 includes acollar 103. The collar 103 includes a first collar end surface 104, asecond collar end surface 105, and an outer collar surface 106positioned between the first collar end surface 104 and a second collarend surface 105. In an aspect, the outer collar surface 106 can includea collar gripping surface 107 configured to improve a grip of the collar103. As shown, the collar gripping surface 107 can take the form of aknurled surface for manually torqueing of the collar 103. Alternatively,the collar gripping surface 107 can take other forms, such as the of aplurality of faces for torqueing the collar 103 with a tool.

The optical target 120 includes a two-dimensional pattern thereon 122.In one example, the two-dimensional pattern thereon 122 can be aplurality of a pattern of dots 123 disposed around the cylindricalexterior surface 121 of the optical target 120. In an aspect, thepattern of dots 123 can be unique such that the pattern of dots 123 onan optical target 120 of a hole location target 10 is different from thepattern of dots 123 on an optical target 120 of another hole locationtarget 10. In another example, the two-dimensional pattern thereon 122can be a plurality of a two-dimensional barcodes 125 disposed around thecylindrical exterior surface 121 of the optical target 120. In anaspect, the two-dimensional barcode 125 can be unique such that thetwo-dimensional barcode 125 on an optical target 120 of a hole locationtarget 10 is different from the two-dimensional barcode 125 on anoptical target 120 of another hole location target 10.

In an aspect, the two-dimensional pattern 122 can have a predeterminedcalibration with respect to the centerline 111 of the self-centeringinsert 110, such as a predetermined six degree of freedom calibrationwith respect to the centerline 111 of the self-centering insert 110. Thepredetermined calibration of the two-dimensional pattern 122 can be usedto precisely determine the centerline 111 of the self-centering insert110 based on a determined position of the two-dimensional pattern 122.

In an example, the two-dimensional pattern 122 includes aretroreflective material. By way of including a retroreflective materialin the two-dimensional pattern 122, images of the two-dimensionalpattern 122 may be captured by emitting light to the retroreflectivematerial of the two-dimensional pattern 122 on the cylindrical exteriorsurface 121 of the optical target 120 and capturing light reflected bythe retroreflective material.

FIG. 5 is a representation of an exemplary hole location measurementsystem according to the first embodiment of the present description.

The hole location measurement system 100 of the first embodiment of thepresent description includes the hole location target 10 as describedabove, a camera system 40, and a computer system 50 in communicationwith the camera system 40. As shown, the camera system 40 is configuredto capture images of the two-dimensional pattern 122 on the opticaltarget 120. As shown, the computer system 50 is configured to measurethree-dimensional locations of features of the two-dimensional pattern122 on the optical target 120 and to extract a location of a cylinderaxis of the cylinder surface geometry. In an aspect, the computer systemis configured to measure three-dimensional locations of features of thetwo-dimensional pattern on a cylindrical exterior surface of the opticaltarget, to fit the three-dimensional locations of the features of thetwo-dimensional pattern to a cylinder surface geometry, and to extract alocation of a cylinder axis of the cylinder surface geometry. Thecomputer system 50 may be separate from or integrated with the camerasystem 40.

In an aspect, hole location measurement system 100 includes a pluralityof the hole location targets 10. In another aspect, the camera system 40is configured to capture images of the two-dimensional patterns 122 ofthe plurality of the hole location targets 10. In yet another aspect, asingle image captured by the camera system 40 includes thetwo-dimensional patterns 122 of the plurality of the hole locationtargets 10. Thus, by capturing the two-dimensional patterns 122 of theplurality of the hole location targets 10 in a single image, the holelocation measurement system 100 enables for single camera, single shotmeasurements of multiple holes at the same time.

In an aspect, the camera system 40 is a three-dimensional opticalscanner. In another aspect, the camera system is a portablethree-dimensional optical scanner. Alternatively, the three-dimensionaloptical scanner may be of a type supported on an articulating arm.

As illustrated, the portable three-dimensional optical scanner is shownas a stereo camera-styled scanner, having a pair of spaced lensesconfigured to acquire real-time data from a plurality of poses,utilizing a grid style coordinate system to generate and transfer 3-Dimages.

In yet another aspect, the portable three-dimensional optical scannerincludes an inertial navigation system. The inertial navigation systemcontained within the portable three-dimensional optical scanner providesa fixed point of reference, relative to an X-Y-Z set of commoncoordinates on which each scanned pose is based, irrespective ofoperator positioning of the physical scanner device. Thus, the angle andtiming of each pose, i.e. orientation of the scanner in space and timerelative to the target, is assured via the inertial navigation system tohave a common frame of reference.

FIG. 6 is a flow diagram of an exemplary method for measuring a locationof a hole H of a workpiece W according to the first embodiment of thepresent description.

The method 1000 includes, at block 1002, centering an insert within ahole H having a centerline C. The insert can be the self-centered insert110 or can be a different insert that is centered by any external means.

An optical target 120 is attached to the insert at a fixed positionrelative to the centerline 111 of the self-centering insert 110. Theoptical target 120 includes a two-dimensional pattern 122 thereon.

The method 1000 further includes, at block 1004, capturing images of thetwo-dimensional pattern 122 on the optical target 120. The images can becaptured by the camera system 40 as described above. In an aspect, thestep of capturing images, at block, 1004, includes emitting light to aretroreflective material of the two-dimensional pattern 122 on theoptical target 120 and capturing light reflected by the retroreflectivematerial.

The method 1000 further includes, at block 1006, measuringthree-dimensional locations of features of the two-dimensional pattern122 on the optical target 120, at block 1008, extracting a location ofthe centerline 111 of the self-centering insert 110 based on thethree-dimensional locations of features of the two-dimensional pattern122 and the fixed position of the optical target 120 relative to thecenterline 111 of the self-centering insert 110. Each of these steps canbe performed by the camera system 40, the computer system 50, or thecamera system 40 integrated with the computer system 50.

The step 1006 of measuring three-dimensional locations of features ofthe two-dimensional pattern 122 on the optical target 120 is performedby analysis of the of the images captured by the camera system 40 toidentify the two dimensional pattern of the optical target within theacquired image and to determine distance relative to the optical targetbased on a measure of target features within the image.

In an example, measuring three-dimensional locations of features of thetwo-dimensional pattern 122 on the optical target 120 includes measuringthree-dimensional locations of dot centroids of a pattern of dots 123 ofthe two-dimensional pattern 122 shown in FIG. 1. Each dot of the patternof dots 123 has a centroid which can be determined from the imagescaptured by the camera system 40, and each centroid has a specificthree-dimensional location. Thus, by measuring the three-dimensionallocations of each dot centroid as captured by the camera system 40, aplurality of precise three-dimensional locations on the optical target120 can be found.

In another example, measuring three-dimensional locations of features ofthe two-dimensional pattern 122 on the optical target 120 includesmeasuring three-dimensional locations of intersections of atwo-dimensional barcode 125 of the two-dimensional pattern 122 shown inFIG. 2. Each line of the two-dimensional barcode 125 defines aone-dimensional vector in three-dimensional space, which can bedetermined from the images captured by the camera system 40, and theintersection of two lines of the two-dimensional barcode 125 defines aspecific three-dimensional location. Thus, by measuring thethree-dimensional locations of intersections of a barcode pattern ascaptured by the camera system 40, a plurality of precisethree-dimensional locations on the optical target 120 can be found.

The step 1008 of fitting the three-dimensional locations of the featuresof the two-dimensional pattern 122 to a cylinder surface geometry can beperformed by, for example, calculating a best fit of thethree-dimensional locations of the features to a cylinder surfacegeometry. Thus, the plurality of precise three-dimensional locations onthe optical target 120 can be used to accurately find a cylinder surfacegeometry of the optical target 120.

The step 1010 of extracting a location of a cylinder axis of thecylinder surface geometry can be performed by, for example, calculatinga best fit of a cylinder axis to the cylinder surface geometry. Byextracting the location of the cylinder axis, the extracted cylinderlocation of the cylinder axis can be precisely equated to a centerlineof the hole H of the workpiece W.

In an aspect, the method 1000 further includes comparing thethree-dimensional locations of features of the two-dimensional pattern122 on the optical target 120 to a database of three-dimensionallocations of features of known optical targets. As shown in FIG. 5, thetwo-dimensional pattern 122 on the optical target 120 can be unique.Thus, the method 1000 can correlate a unique optical target 120 to aunique location of the hole H of the workpiece W.

FIG. 7 is a perspective view of a first exemplary hole location targetaccording to a second embodiment of the present description in anassembled state. FIG. 8 is a perspective view of a second exemplary holelocation target according to the second embodiment of the presentdescription in an assembled state. FIG. 9 is an exploded perspectiveview of the hole location target of FIG. 7. FIG. 10A is cross-sectionalview of the hole location target of FIG. 7 inserted into a hole of aworkpiece W in a radially contracted state. FIG. 10B is cross-sectionalview of the hole location target of FIG. 10A in a radially expandedstate.

Referring to FIGS. 7, 8, 9, 10A, 10B, 11, and 12, the hole locationtarget 20 includes a first end 201 configured to be inserted into a holeH of a workpiece W and a second end 202 opposite to the first end 201.

The hole location target 20 includes a self-centering insert 210 and anoptical target 220 attached to the self-centering insert 210. Theself-centering insert 210 is positioned near the first end 201 and theoptical target 220 is positioned near the second end 202 such that theself-centering insert 210 can be inserted into the hole H of theworkpiece and the optical target 220 can remain outside of the hole H ofthe workpiece W.

The self-centering insert 210 has a centerline 211 and the opticaltarget 220 is attached to the self-centering insert 210 at a fixedposition relative to the centerline 211 of the self-centering insert210, and the optical target 220 includes a light-emitting display 270.By attaching the optical target 220, including the light-emittingdisplay 270, to the self-centering insert 210 at a fixed positionrelative to the centerline 211 of the self-centering insert 210, amethod that measures a location of the light-emitting display 270 can beemployed to determine a location of the centerline 211 of theself-centering insert 210, which can be correlated to the location ofthe centerline C of the hole H of the workpiece W.

The self-centering insert 210 is configured to be inserted into the holeH of the workpiece W and to be self-centered such that the centerline211 of the self-centering insert 210 is positioned coaxially with arespective centerline C of the hole H of the workpiece W. By centeringthe centerline 211 of the self-centering insert 210 to be coaxial withthe centerline C of the hole H of the workpiece W, a method thatmeasures a location of the centerline 211 of the self-centering insert210 can be employed to determine a location of the centerline C of thehole H of the workpiece W. Furthermore, by making the optical target 220at a fixed position (or known offset) relative to the centerline 211 ofthe self-centering insert 210, a method that measures a location of theoptical target 220 can be employed to determine the location of thecenterline 211 of the self-centering insert 210 and, thus, to determinethe location of the centerline C of the hole H of the workpiece W. In anaspect, the self-centering insert 210 can include a bore 217 foraccommodating a compression device 230.

In the illustrated example, the self-centering insert 210 of the firstembodiment includes a radially expandable bushing 212. It will beunderstood that the radially expandable bushing 212 can include anytubular structure capable of inserting into the hole H of the workpieceW and capable of radially expanding to self-center the centerline 211 ofthe self-centering insert 210 to the centerline C of the hole H of theworkpiece W. In the illustrated example, the radially expandable bushing212 takes the form of an expandable bellows 214. In an alternativeexample, the radially expandable bushing 212 can take the form of anexpandable collet such as is illustrated with respect to the thirdembodiment below.

The expandable bellows 214 of the present description is a tubularstructure in which an axial contraction of the expandable bellows 214translates into a radial expansion of expandable bellows 214 and anaxial expansion of the expandable bellows 214 translates into a radialcontraction of expandable bellows 214. In the illustrated example, theexpandable bellows 214 includes a first bellows end 215 and a secondbellows end 216 and one or more radial ridges 218 between the firstbellows end 215 and the second bellows end 216. By axially contractingthe expandable bellows 214, the one or more radial ridges 218 expandradially. By axially expanding the expandable bellows 214, the one moreradial ridges 218 contract radially.

As shown in FIG. 10A, by axially expanding the expandable bellows 214,the one or more radial ridges 218 contract radially, thereby permittingthe expandable bellows 214 to be inserted into a hole H of a workpieceW. As shown in FIG. 10B, after inserting the expandable bellows 214 intothe hole H of the workpiece W, the expandable bellows 214 can be axiallycontracted to radially expand one or more radial ridges 218. The one ormore radial ridges 218 then contact the walls defining the hole H of theworkpiece W, thus causing a self-centering of the centerline 211 of theexpandable bellows 214 to the respective centerline C of the hole H ofthe workpiece W.

In the illustrated example, the optical target 220 is attached to theself-centering insert 110 such that the optical target 220 is at a fixedposition relative to the centerline 211 of the self-centering insert210. The fixed positioning of the optical target 220 with respect to theposition of centerline 211 of the self-centering insert 210 can bepermanent. As shown, the self-centering insert 210 and a target support203 for supporting the optical target 220 can be combined as amonolithic body. For improved precision, the self-centering insert 210and the target support 203 can be unitary formed together as amonolithic body by one or more processes, such as casting, molding, andadditive manufacturing.

In the illustrated example, the self-centering insert 210 includes acompression device 230 configured to axially contract the expandablebellows 214. In the illustrated example, the compression device 230includes a bolt 240 and a nut 260.

As shown, the bolt 240 has a first bolt end 241 and a second bolt end242. The bolt 240 includes a bolt shaft 243 positioned at the first boltend 241 of the bolt 240 and a bolt head 244 positioned at the secondbolt end 242 of the bolt 240. The bolt shaft 243 includes a first shaftend 245 and a second shaft end 246. Exterior threads 247 are positionedat the first shaft end 245 of the bolt shaft 243, and the bolt head 244is joined to the second shaft end 246. The bolt head 244 includes afirst bolt head end 248 and a second bolt head end 249. A first boltface 251 is positioned at the first bolt head end 248, a second boltface 252 is positioned at the second bolt head end 249, and an outerbolt head surface 250 is positioned between the first bolt head end 248and the second bolt head end 249. The outer bolt head surface 250 cantake the form of a plurality of faces extending around a circumferenceof the bolt head 244 to improve torqueing of the bolt 240.

As shown, the nut 260 has a first nut end 261 and a second nut end 262.A first nut face 263 is positioned at the first nut end 261, a secondnut face 264 is positioned at the second nut end 262, and an outer nutsurface 265 is positioned between the first nut end 261 and the secondnut end 262. As shown, the nut gripping surface 266 can take the form ofa plurality of faces for improve retention with the self-centeringinsert 210. The nut bore 267 passes through the nut 260 from the firstnut face 263 to the second nut face 264, and the nut bore 267 includesinterior threads 268 configured to engage with the exterior threads 247of the bolt 240.

As shown, the bolt shaft 243 passes through bore 217 at the firstbellows end 215 through the expandable bellows 214 to the second bellowsend 216, and the exterior threads 247 of the bolt 240 engage with theinterior threads 268 of the nut 260. The bolt 240 engages with the firstbellows end 215 and the nut 260 engages with the second bellows end 216.Thus, the bolt 240 and nut 260 form a compression device 230 configuredto contract the expandable bellows 214 by turning the bolt 240. However,the compression device 230 is not limited to the above-describedexample. In another example, the position of the bolt 240 and nut 260may be reversed. In yet another example, the compression device 230 maytake the form of a rachet or any other compression device configured toaxially contract the expandable bellows 214.

As previously mentioned, the optical target 220 includes alight-emitting display 270. The light-emitting display 270 includes, forexample, a liquid crystal display (LCD), a light emitted diode (LED), anorganic light-emitting diode (OLED), or a quantum dot light emittingdiodes (QLED). The light-emitting display 270 includes a two-dimensionalpattern 222 thereon. By measuring a location of the light-emittingdisplay 270, a location of the centerline 211 of the self-centeringinsert 210 can be determined, which can be correlated to the location ofthe centerline C of the hole H of the workpiece W. In an aspect, thetwo-dimensional pattern 22 can have a predetermined calibration withrespect to the centerline 211 of the self-centering insert 210, such asa predetermined six degree of freedom calibration with respect to thecenterline 211 of the self-centering insert 210. The predeterminedcalibration of the two-dimensional pattern 222 can be used to preciselydetermine the centerline 211 of the self-centering insert 210 based on adetermined position of the two-dimensional pattern 222. Furthermore, byway emitting light from the light-emitting display 270, thetwo-dimensional pattern 222 thereon can be more easily captured by acamera system.

In the example shown in FIG. 7, the two-dimensional pattern 222 thereoncan a plurality of a pattern of dots 223. In an aspect, the pattern ofdots 223 can be displayed to be unique such that the pattern of dots 223on an optical target 220 of a hole location target 20 is different fromthe pattern of dots 223 displayed on an optical target 220 of anotherhole location target 20. The three-dimensional locations of dotcentroids of the pattern of dots 223 of the two-dimensional pattern 222can be determined. Each dot of the pattern of dots 223 has a centroidwhich can be determined from the images captured by a camera system, andeach centroid has a specific three-dimensional location. Thus, bymeasuring the three-dimensional locations of each dot centroid, aplurality of precise three-dimensional locations of the light-emittingdisplay 270 of the optical target 220 can be found.

In another example shown in FIG. 8, the two-dimensional pattern 222thereon can a plurality of a two-dimensional barcode 225 displayed bythe optical target 220. In an aspect, the two-dimensional barcode 225can be displayed to be unique such that the two-dimensional barcode 225on an optical target 220 of a hole location target 20 is different fromthe two-dimensional barcode 225 displayed on an optical target 220 ofanother hole location target 20. Each line of the barcode patterndefines a one-dimensional vector in three-dimensional space, which canbe determined from the images captured by a camera system, and theintersection of two lines of the barcode pattern defines a specificthree-dimensional location. Thus, by measuring the three-dimensionallocations of intersections of a barcode pattern, a plurality of precisethree-dimensional locations on the light-emitting display 270 of theoptical target 220 can be found.

Furthermore, by way of including a light-emitting display 270 in theoptical target 220, the optical target 220 can preferably modify thetwo-dimensional pattern 222 of the optical target 220. Modifying thetwo-dimensional pattern 222 can include, for example, changing a size ofthe two-dimensional pattern, modifying an intensity of light of thelight-emitting display 270, modifying a wavelength of light of thelight-emitting display 270, and temporal modulation of light of thelight-emitting display 270.

FIG. 11 is a representation of an exemplary hole location measurementsystem according to the second embodiment of the present description.

The hole location measurement system 200 includes the hole locationtarget 20, a camera system 40 configured to capture images of thetwo-dimensional pattern 222 of the optical target 220, and a computersystem 50 in communication with the camera system 40 and incommunication with hole location target 20. The computer system 50 isconfigured to control modification of the two-dimensional pattern 222 ofthe optical target 220 and to determine three-dimensional coordinates ofthe centerline 211 of the self-centering insert from the images of thetwo-dimensional pattern 222 of the optical target 220. The computersystem 50 may be separate from or integrated with the camera system 40.

In an aspect, hole location measurement system 200 includes a pluralityof the hole location targets 20. In another aspect, the camera system 40is configured to capture images of the two-dimensional patterns 222 ofthe plurality of the hole location targets 20. In yet another aspect, asingle image captured by the camera system 40 includes thetwo-dimensional patterns 222 of the plurality of the hole locationtargets 20. Thus, by capturing the two-dimensional patterns 222 of theplurality of the hole location targets 20 in a single image, the holelocation measurement system 200 enables for single camera, single shotmeasurements of multiple holes at the same time.

In an aspect, the camera system 40 is a three-dimensional opticalscanner. In another aspect, the camera system is a portablethree-dimensional optical scanner. Alternatively, the three-dimensionaloptical scanner may be of a type supported on an articulating arm.

As illustrated, the portable three-dimensional optical scanner is shownas a stereo camera-styled scanner, having a pair of spaced lensesconfigured to acquire real-time data from a plurality of poses,utilizing a grid style coordinate system to generate and transfer 3-Dimages.

The portable three-dimensional optical scanner can include an inertialnavigation system. The inertial navigation system contained within theportable three-dimensional optical scanner provides a fixed point ofreference, relative to an X-Y-Z set of common coordinates on which eachscanned pose is based, irrespective of operator positioning of thephysical scanner device. Thus, the angle and timing of each pose, i.e.orientation of the scanner in space and time relative to the target, isassured via the inertial navigation system to have a common frame ofreference.

In an aspect, the light-emitting display 270 and the camera system 40can include at least one of matching polarized filters and matchingwavelength filters. By way of matching a polarized filter and/or awavelength filter of the light-emitting display 270 and the camerasystem 40, a capability of a hole location measurement system 200 tocapture images of the two-dimensional patterns 222 of the plurality ofthe hole location targets 20 can be enhanced.

FIG. 12 is a flow diagram of an exemplary method for measuring alocation of a hole H of a workpiece W according to the second embodimentof the present description.

The method 2000 for measuring a location of a hole H includes, at block2002, centering an insert within a hole having a centerline. The insertcan be the self-centered insert 210 or can be a different insert that iscentered by any external means. The optical target 220 is attached tothe insert at a fixed position relative to the centerline 211 of theinsert. The optical target 220 includes the light-emitting display 270comprising a two-dimensional pattern 222 thereon. In an example, thetwo-dimensional pattern 222 can include, for example, the pattern ofdots 223 or the two-dimensional barcode 225.

The method 2000 further includes, at block 2004, capturing images of thetwo-dimensional pattern 222 of the optical target. The images can becaptured by the camera system 40 as described above.

The method 2000 further includes, at block 2006, modifying thetwo-dimensional pattern 222 of the optical target 220.

The method 2000 further includes, at block 2008, capturing images of themodified two-dimensional pattern 222 of the optical target 220. Theimages can be captured by the camera system 40 as described above.

In step 2006, modifying the two-dimensional pattern 222 can include, forexample, changing a size of the two-dimensional pattern, modifying anintensity of light of the light-emitting display 270, modifying awavelength of light of the light-emitting display 270, and temporalmodulation of light of the light-emitting display 270.

Changing a size of the two-dimensional pattern 222 can include, forexample, increasing or decreasing size of each dot of the pattern ofdots 223 or increasing or decreasing a size of a bar of thetwo-dimensional barcode 225. By way of increasing or decreasing a sizeof the two-dimensional pattern 222, the method 2000 can compensate for adistance between the camera system 40 and the hole location target 20.In an exemplary aspect, the camera system 40, alone or by way of thecomputer system 50, can control a size of the two-dimensional pattern222. Thus, the method 2000 can provide for an interactive control of thesize of the two-dimensional pattern 222 based on real-time feedback fromthe camera system 40 capturing the images of the two-dimensional pattern222.

By way of modifying an intensity of light of the light-emitting display270, the method 2000 can compensate for environmental conditions, e.g.intensity of background light. In an exemplary aspect, the camera system40, alone or by way of the computer system 50, can control an intensityof light of the two-dimensional pattern 222. Thus, the method 2000 canprovide for an interactive control of the intensity of thetwo-dimensional pattern 222 based on real-time feedback from the camerasystem 40 capturing the images of the two-dimensional pattern 222.

By way of modifying a wavelength of light of the light-emitting display270, the method 2000 can compensate for environmental conditions bydistinguishing the wavelength of light emitted from the light-emittingdisplay 270. In an exemplary aspect, the camera system 40, alone or byway of the computer system 50, can control a wavelength of light of thetwo-dimensional pattern 222. Thus, the method 2000 can provide for aninteractive control of the wavelength of the two-dimensional pattern 222based on real-time feedback from the camera system 40 capturing theimages of the two-dimensional pattern 222.

By way of temporal modulation of light of the light-emitting display270, the method 2000 can compensate for environmental conditions.Temporal modulation of light can include, for example, a blinking oflight of the light-emitting display 270. In an exemplary aspect, thecamera system 40, alone or by way of the computer system 50, can controla of temporal modulation of light of the two-dimensional pattern 222.Thus, the method 2000 can provide for an interactive control of thephase of the two-dimensional pattern 222 based on real-time feedbackfrom the camera system 40 capturing the images of the two-dimensionalpattern 222.

Thus, as described above, modifying the two-dimensional pattern 222 ofthe optical target 220 by the camera system 40, alone or by way of thecomputer system 50, can provide for method 2000 that adjusts the opticaltarget 220 to the conditions at the time of taking the measurements.

In another aspect, modifying the two-dimensional pattern 222 of theoptical target 220 can communicate a status of the hole location target20. Thus, modifying the two-dimensional pattern 222 can communicate asignal with a status of the hole location target 20, which can includecorrelating the signal with an identity of the hole location target.

FIG. 13 is a perspective view of an exemplary hole location targetaccording to a third embodiment of the present description in anassembled state. FIG. 14 is an exploded perspective view of the holelocation target of FIG. 13. FIG. 15A is cross-sectional view of the holelocation target of FIG. 13 inserted into a hole of a workpiece W in aradially contracted state. FIG. 15B is cross-sectional view of the holelocation target of FIG. 15A in a radially expanded state.

Referring to FIGS. 13, 14, 15A, and 15B, the hole location target 30includes a first end 301 configured to be inserted into a hole H of aworkpiece W and a second end 302 opposite to the first end 301.

The hole location target 30 includes a self-centering insert 310 and alaser beam emitter 320 attached to the self-centering insert 310. Theself-centering insert 310 is positioned near the first end 301 and thelaser beam L is emitted near the second end 302 such that theself-centering insert 310 can be inserted into the hole H of theworkpiece and the laser beam L can be emitted outside of the hole H ofthe workpiece W. The self-centering insert 310 has a centerline 311 andthe axis of the emitted laser beam L is concentric to the centerline 311of the self-centering insert 310.

The self-centering insert 310 is configured to be inserted into the holeH of the workpiece W and to be self-centered such that the centerline311 of the self-centering insert 310 is positioned coaxially with arespective centerline C of the hole H of the workpiece W. By centeringthe centerline 311 of the self-centering insert 310 to be coaxial withthe centerline C of the hole H of the workpiece W, a method thatmeasures a location of the centerline 311 of the self-centering insert310 can be employed to determine a location of the centerline C of thehole H of the workpiece W. Furthermore, by making the axis of theemitted laser beam L to be concentric to the centerline 311 of theself-centering insert 310, a method that measures the location of theemitted laser beam L can be employed to determine the location of thecenterline 311 of the self-centering insert 310 and, thus, to determinethe location of the centerline C of the hole H of the workpiece W. In anaspect, the axis of the emitted laser beam is concentric to thecenterline of the self-centering insert to 5 μm or less.

In the illustrated example, the self-centering insert 310 of the firstembodiment includes a radially expandable bushing 312. It will beunderstood that the radially expandable bushing 312 can include anytubular structure capable of inserting into the hole H of the workpieceW and capable of radially expanding to self-center the centerline 311 ofthe self-centering insert 310 to the centerline C of the hole H of theworkpiece W. In the illustrated example, the radially expandable bushing312 takes the form of an expandable collet 314. In an alternativeexample, the radially expandable bushing 312 can take the form of anexpandable bellows such as is illustrated with respect to the first andthird embodiments above.

The expandable collet 314 of the present description is a tubularstructure in which radially outward force applied to the expandablecollet 314 radially expands the expandable collet 314.

In the illustrated example, the expandable collet 314 includes a firstcollet end 315 and a second collet end 316 and axial beams 318 betweenthe first collet end 315 and the second collet end 316. By applying aradially outward force to the expandable collet 314, the axial beams 318circumferentially separate and expand radially outward.

As shown in FIG. 15A, reducing the radially outward force applied to theexpandable collet 314, the axial beams 318 contract radially, therebypermitting the expandable collet 314 to be inserted into a hole H of aworkpiece W. As shown in FIG. 15B, after inserting the expandable collet314 into the hole H of the workpiece W, the radially outward force isapplied to the expandable collet 314 and the axial beams 318 radiallyexpand. The axial beams 318 then contact the walls defining the hole Hof the workpiece W, thus causing a self-centering of the centerline 311of the expandable collet 314 to the respective centerline C of the holeH of the workpiece W.

In the illustrated example, the laser beam emitter 320 is attached tothe self-centering insert 310 such that the emitted laser beam L isconcentric to the centerline 311 of the self-centering insert 310. Byway of example, the laser beam emitter 320 can be fixedly positioned tothe self-centering insert 310 such that a position of the laser beamemitter 320 is fixed with respect to a position of centerline 311 of theself-centering insert 310. The positioning of the laser beam emitter 320with respect to the position of centerline 311 of the self-centeringinsert 310 can be permanent.

In the illustrated example, the self-centering insert 310 includes anexpansion device 330 configured to apply a force to radially expand theexpandable collet 314. In the illustrated example, the expansion device330 includes a first wedge 340, a second wedge 350, and a collar 360.

As shown, the first wedge 340 has a first wedge lower end 341, a firstwedge upper end 342 opposite to the first wedge lower end 341, and afirst hollow shaft 343 between the first wedge lower end 341 and thefirst wedge upper end 342. A first inclined wedge surface 344 ispositioned at the first wedge lower end 341 of the first wedge 340. Thefirst inclined wedge surface 344 is configured to engage with aninclined collet surface of the expandable collet 314. Exterior threads345 are positioned on an exterior surface of the first hollow shaft 343,and a wedge grip 346 is positioned at the first wedge upper end 342 ofthe first wedge 340. The wedge grip 346 can include a wedge grippingsurface 348. The wedge gripping surface 348 can take the form of aknurled surface for improved manually torqueing of the wedge grip 346.Alternatively, the wedge gripping surface 348 can take other forms, suchas the of a plurality of faces for torqueing the wedge grip 346 with atool. The first wedge 340 is sized to pass through an first end of ahollow interior of the expandable collet 314 such that the firstinclined wedge surface 344 engages with the inclined collet surface 319and such that the exterior threads 345 and wedge grip 346 extend past asecond end of the hollow interior of the expandable collet 314.

As shown, the second wedge 350 has a second wedge lower end 351, asecond wedge upper end 352 opposite to the second wedge lower end 351,and a second hollow shaft 353 between the second wedge lower end 351 andthe second wedge upper end 352. A second inclined wedge surface 354 ispositioned at the second wedge upper end 352 of the second wedge 350.The second inclined wedge surface 354 is configured to engage with aninclined collet surface 319 of the expandable collet 314. The secondhollow shaft 353 is sized to pass through the hollow interior of theexpandable collet 314 such that the second inclined wedge surface 354engages with the inclined collet surface 319.

By engagement of the first inclined wedge surface 344 and the secondinclined wedge surface 354 with the inclined collet surfaces 319, anaxial movement of the first wedge 340 towards the second wedge 350results in a radially outward force applied to the expandable collet 314to circumferentially separate and radially expand the axial beams 318.

The collar 360 can provide axial movement of the first wedge 340 towardsthe second wedge 350. As shown, the collar 360 includes a first collarportion 361 and a second collar portion 366.

The first collar portion 361 has a first collar lower end 362 and afirst collar upper end 363. The first collar upper end 363 can include awavy upper surface 364 configured to engage with a corresponding wavysurface of the second collar portion, and a first collar bore 365 passesthrough the first collar portion 361 from the first collar lower end 362to the first collar upper end 363.

The second collar portion 366 has a second collar lower end 367 and asecond collar upper end 368. The second collar portion 366 can include asecond collar gripping surface 369. The second collar gripping surface369 can take the form of a knurled surface for improved manuallytorqueing of the second collar gripping surface 369. Alternatively, thesecond collar gripping surface 369 can take other forms, such as the ofa plurality of faces for torqueing the second collar gripping surface369 with a tool. The second collar portion 366 includes interior threads370 in a bore passing through the second collar portion 366 from thesecond collar lower end 367 to the second collar upper end 368. Theinterior threads 370 of the second collar portion 366 are configured toengage with the exterior threads of the first wedge 340 to axially movethe first wedge 340 towards the second wedge 350.

Thus, the first wedge 340, the second wedge 350, and the collar 360 forman expansion device 330 configured to apply a radially outward force tothe expandable collet 314 by turning the collar 360. However, theexpansion device 330 is not limited to the above-described example. Inanother example, the position of the first wedge 340, the second wedge350, and the collar 360 can be reversed. In yet another example, theexpansion device 330 may take the form of a spring or any otherexpansion device configured to radially expand the expandable collet314.

As shown, the hole location target 30 further includes a power device380. In the illustrated example, the power device 380 includes a battery381, a power switch 382, and a conduit 383. However, the power device380 is not limited to the above-described example. In another example,the power device 380 could include a wire connected to an electricitysupply.

FIG. 16A is a representation of an exemplary hole location measurementsystem according to the third embodiment of the present description,including an optical sensor at a first distance d1 from the laser beamemitter. FIG. 16B is a representation of the exemplary hole locationmeasurement system according to the third embodiment of the presentdescription, including the optical sensor at a second distance d2 fromthe laser beam emitter.

The hole location measurement system 300 includes the hole locationtarget 30, in which the axis of the emitted laser beam L is concentricto the centerline 311 of the self-centering insert 310, an opticalsystem 41 sensing the location of the emitted laser beam L at multipledistances from the laser beam emitter 320, and a computer system 50 incommunication with the hole location target 30 and optionally theoptical system 41. The computer system 50 is configured to determinethree-dimensional coordinates of the centerline 311 of theself-centering insert 310 from the sensed locations of the emitted laserbeam L. The optical system 41 includes any optical system capable ofsensing the location of the emitted laser beam L at multiple distancesfrom the laser beam emitter 320. The computer system 50 may be separatefrom or integrated with the camera system 40.

In an aspect, hole location measurement system 300 includes a pluralityof the hole location targets 30. In another aspect, the optical system41 is configured to sense the location of multiple emitted laser beams Lat the same time. Thus, by sensing the location of multiple emittedlaser beams L at the same time, the hole location measurement system 300enables for measurements of multiple holes at the same time.

The optical system 41 can be a portable optical system. Alternatively,the optical system 41 is of a type supported on an articulating arm.

In an aspect, the laser beam emitter 320 is configured to modulate apower of the emitted laser beam L. By controlling modulation of theemitted laser beam L, laser beam emitter 320 can compensate forenvironmental conditions, e.g. intensity of background light.

In another aspect, the optical system 41 and/or the computer system 50is configured to control the modulation of the emitted laser beam L. Bycontrolling modulation of the emitted laser beam L, the hole locationmeasurement system 300 can compensate for environmental conditions, e.g.intensity of background light, by modulating the emitted laser beam L tofacilitate sensing of the emitted laser beam L by the optical system 41.Thus, the hole location measurement system 300 can provide for aninteractive control of the modulation of the emitted laser beam L basedon real-time feedback from the optical system 41 sensing the location ofemitted laser beam L.

Furthermore, in an aspect, the emitted laser beam L is modulated to senda signal, and the computer system 50 is configured to extract a signalfrom the modulated powder of the emitted laser beam L. The signal can beindicative of a status of the hole location target, an identity of thehole location target, or a status of the laser beam emitter.

In an aspect, the laser beam emitter 320 and the optical system 41 caninclude at least one of matching polarized filters and matchingwavelength filters. By way of matching a polarized filter and/or awavelength filter of the laser beam emitter 320 and the optical system41, a capability of a hole location measurement system 300 to sense thelocation of the emitted laser beam L can be enhanced.

FIG. 17 is a flow diagram of an exemplary method for measuring alocation of a hole of a workpiece W according to the third embodiment ofthe present description.

The method 3000 for measuring a location of a hole H includes, at block3002, centering an insert within a hole having a centerline. The insertcan be the self-centered insert 310 or can be a different insert that iscentered by any external means.

The method 3000 further includes, at block 3004, emitting a laser beamfrom a laser beam emitter attached to the insert, wherein the axis ofthe emitted laser beam is concentric to the centerline of the insert.

The method 3000 further includes, at block 3006, sensing the location ofthe emitted laser beam at multiple distances from the laser beamemitter.

The method 3000 further includes, at block 3008, determiningthree-dimensional coordinates of the centerline of the self-centeringinsert from the sensed locations of the emitted laser beam.

In an aspect, the method 3000 further includes modulating a power of theemitted laser beam and extracting a signal from the modulated powder ofthe emitted laser beam. In another aspect, the method 3000 furtherincludes correlating the signal with a status of the hole locationtarget.

In an aspect, the method 3000 further includes correlating the signalwith an identity of the hole location target.

In an aspect, the method 3000 further includes correlating the signalwith a status of the laser beam emitter.

In an aspect, the method 3000 further includes rotating an articlehaving the hole therein, emitting the laser beam from the laser beamemitter during the rotating, sensing the location of the emitted laserbeam at multiple distances from the laser beam emitter during therotating, and determining three-dimensional coordinates of thecenterline of the self-centering insert throughout the rotation fromsensed locations of the emitted laser beam.

Examples of the present disclosure may be described in the context of anaircraft manufacturing and service method 4000, as shown in FIG. 18, andan aircraft 4002, as shown in FIG. 19. During pre-production, theaircraft manufacturing and service method 4000 may include specificationand design 4004 of the aircraft 4002 and material procurement 4006.During production, component/subassembly manufacturing 4008 and systemintegration 4010 of the aircraft 4002 takes place. Thereafter, theaircraft 4002 may go through certification and delivery 4012 in order tobe placed in service 4014. While in service by a customer, the aircraft4002 is scheduled for routine maintenance and service 4016, which mayalso include modification, reconfiguration, refurbishment and the like.

Each of the processes of method 4000 may be performed or carried out bya system integrator, a third party, and/or an operator (e.g., acustomer). For the purposes of this description, a system integrator mayinclude without limitation any number of aircraft manufacturers andmajor-system subcontractors; a third party may include withoutlimitation any number of venders, subcontractors, and suppliers; and anoperator may be an airline, leasing company, military entity, serviceorganization, and so on.

The hole location targets, hole location measurement systems, andmethods for measuring a location of a hole of the present disclosure maybe employed during any one or more of the stages of the aircraftmanufacturing and service method 1000, including specification anddesign 4004 of the aircraft 4002, material procurement 4006,component/subassembly manufacturing 4008, system integration 4010,certification and delivery 4012, placing the aircraft in service 4014,and routine maintenance and service 4016.

As shown in FIG. 19, the aircraft 4002 produced by example method 4000may include an airframe 4018 with a plurality of systems 4020 and aninterior 4022. Examples of the plurality of systems 4020 may include oneor more of a propulsion system 4024, an electrical system 4026, ahydraulic system 4028, and an environmental system 4030. Any number ofother systems may be included. The hole location targets, hole locationmeasurement systems, and methods for measuring a location of a hole ofthe present disclosure may be employed for any of the systems of theaircraft 4002.

Although various embodiments of the disclosed hole location targets,hole location measurement systems, and methods for measuring a locationof a hole have been shown and described, modifications may occur tothose skilled in the art upon reading the specification. The presentapplication includes such modifications and is limited only by the scopeof the claims.

What is claimed is:
 1. A hole location target comprising: aself-centering insert having a centerline, wherein the self-centeringinsert comprises a radially expandable bushing; -and an optical targetattached to the self-centering insert at a fixed position relative tothe centerline of the self-centering insert, the optical target surfacecomprising a two-dimensional pattern thereon.
 2. The hole locationtarget of claim 1, wherein the optical target has a cylindrical exteriorsurface that is concentric to the centerline of the self-centeringinsert, the cylindrical exterior surface comprising the two-dimensionalpattern thereon.
 3. The hole location target of claim 2 wherein thecylindrical exterior surface of the optical target has a surfacecylindricity of 5 μm or less.
 4. The hole location target of claim 1wherein the radially expandable bushing comprises an expandable bellows.5. The hole location target of claim 1 wherein the radially expandablebushing comprises an expandable collet.
 6. The hole location target ofclaim 1 wherein the two-dimensional pattern comprises a pattern of dots.7. The hole location target of claim 1 wherein the two-dimensionalpattern comprises a two-dimensional barcode.
 8. The hole location targetof claim 1 wherein the two-dimensional pattern comprises aretroreflective material.
 9. A hole location measurement systemcomprising: a hole location target comprising: a self-centering inserthaving a centerline, wherein the self-centering insert comprises aradially expandable bushing; and an optical target attached to theself-centering insert at a fixed position relative to the centerline ofthe self-centering insert, the optical target surface comprising atwo-dimensional pattern thereon; a camera system configured to captureimages of the two-dimensional pattern on the optical target; and acomputer system configured to measure three-dimensional locations offeatures of the two-dimensional pattern on the optical target and toextract a location of the centerline of the self-centering insert. 10.The hole location measurement system of claim 9 comprising a pluralityof the hole location targets.
 11. The hole location measurement systemof claim 10 wherein the camera system is configured to capture one ormore images of the two-dimensional patterns of the plurality of the holelocation targets.
 12. The hole location measurement system of claim 11wherein a single image captured by the camera system includes thetwo-dimensional patterns of the plurality of the hole location targets.13. The hole location measurement system of claim 9 wherein the camerasystem is a three-dimensional optical scanner.
 14. The hole locationmeasurement system of claim 9 wherein the camera system is a portablethree-dimensional optical scanner.
 15. The hole location measurementsystem of claim 9 wherein the radially expandable bushing comprises anexpandable bellows.
 16. The hole location measurement system of claim 9wherein the radially expandable bushing comprises an expandable collet.17. The hole location measurement system of claim 9 wherein thetwo-dimensional pattern comprises a retroreflective material.
 18. Amethod for measuring a location of a hole, the method comprising:centering an insert within a hole having a centerline, wherein anoptical target is attached to the insert at a fixed position relative tothe centerline of the insert, the optical target surface comprising atwo-dimensional pattern thereon; capturing images of the two-dimensionalpattern on the optical target; measuring three-dimensional locations offeatures of the two-dimensional pattern on the optical target; andextracting a location of the centerline of the insert based on thethree-dimensional locations of features of the two-dimensional patternon the optical target and the fixed position of the optical targetrelative to the centerline of the insert, wherein the step of centeringthe insert within the hole includes radially expanding the insert topress against walls of the hole.
 19. The method of claim 18 whereinmeasuring three-dimensional locations of features of the two-dimensionalpattern on the optical target comprises measuring three-dimensionallocations of dot centroids of a pattern of dots of the two-dimensionalpattern.
 20. The method of claim 18 wherein measuring three-dimensionallocations of features of the two-dimensional pattern on the opticaltarget comprises measuring three-dimensional locations of intersectionsof a barcode pattern of the two-dimensional pattern.
 21. The method ofclaim 18 further comprising comparing the three-dimensional locations offeatures of the two-dimensional pattern on the optical target to adatabase of three-dimensional locations of features of known opticaltargets.
 22. The method of claim 18 wherein capturing images comprisesemitting light to a retroreflective material of the two-dimensionalpattern on optical target and capturing light reflected by theretroreflective material.